Company history

Rengo dates itself to 12 April 1909, the day Inoue Teijiro resolved to work for himself; that August he opened a small paper-goods business in Tokyo under the name Sanseisha. Working in Naka-Okachimachi, he had taught himself how to crimp paperboard into ridges, rebuilding an imported cushioning material on a machine of his own making — and he gave the result a name that stuck: 段ボール, danbōru. Japan had no word for the material and no domestic maker of it; Inoue supplied both at once, and the first Japanese corrugating machine he built survives in the Paper Museum in Oji.

Naming a category is a durable advantage, and Sanseisha ran for a decade as a one-man shop on it. But a new packaging material spreading nationwide needs capital, not a proprietor. In May 1920, with the backing of Tokyo Electric, Sanseisha absorbed three rivals — Azuma Shiki, Eiritsusha and Teikoku Shiki — and re-formed as Rengo Shiki Co., Ltd. with capital of ¥2 million. The founder of the trade had become the consolidator of it.

What followed was the decision that shaped everything after. Corrugated board is a commodity: quality cannot separate one maker from another, and a converter that buys its board is squeezed every time raw-material prices rise. So Inoue bought the mills. In 1923 Rengo absorbed a competitor, Nippon Seishi of Osaka (no relation to today’s company of that name), taking its Chibune mill; in December 1930 it opened the converting plant at Yodogawa, and in April 1936 added the paper mill beside it — containerboard to finished box, under one roof.

A capital tie-up with Tokyo Electric in 1936 was followed by the Tokyo plant in 1937 and, after the war, the Nagoya plant in 1948 — a national footprint assembled either side of a near-total loss. Air raids and the forfeiture of overseas assets emptied the company out; the rebuild ran plant by plant and sales office by sales office from 1948, and in May 1949 Rengo listed on the First Section of the Osaka Stock Exchange, adding the capital market to its sources of funds.

The post-war build-out extended the same logic in both directions. The Tonegawa mill (1961) and the Tosu plant (1962) began an acceleration of regional plants whose purpose was as much collection as production: a nationwide waste-paper network feeding company mills that fed company converting plants. Rengo now owned procurement, board and box alike — a structure designed to convert scale into cost in an industry where nothing else could be converted into an advantage.

It worked because Japan’s consumer-goods boom pulled corrugated demand up behind it, turning integration capex into profit. A 1968 industrial survey recorded Rengo as the industry’s No. 1 in integrated corrugated production — the head start won by naming the product, re-won and locked in with mills and collection routes.

Inoue died in November 1963, and the company he had run on personal authority discovered how much of its order had rested on him: labour disputes sharpened, and management drifted from the shop floor. The answer was institutional. A three-year plan in 1968 abolished the pre-war distinction between craftsmen and factory hands and put everyone on salary; in January 1972 the company dropped the old signboard and renamed itself Rengo Co., Ltd. Converting a founder’s firm into an organization was the work of the decade after his death — and the precondition for everything attempted abroad and in industry restructuring later.

The 1975 oil shock left containerboard in deep oversupply. Rengo joined a recession cartel and cut costs, yet kept building — the New Kyoto mill in 1975, Chiba in 1985, Sanda in 1993 — because a vertically integrated maker cannot let its mills age without losing the integration itself. Investing through the downturns is precisely what raised Rengo’s relative position each time the industry consolidated.

From 1990 the company began widening beyond the box: a joint venture in Malaysia, a new flexible-packaging sales department, then Howa Sangyo brought into the group in 1998. In April 1999 Rengo merged with Settsu — a deal that deepened its relationship with Sumitomo Corporation and, in 2000, brought Otsubo Kiyoshi from the trading house to the presidency. A self-contained corrugated specialist had hired in outside reach.

Otsubo used the trading house’s convening power to make Rengo the industry’s restructurer — absorbing Fukui Chemical, folding in Niigata Danboru and Asahikawa Rengo, pushing a general-packaging line alongside the core box. In November 2006 he went further, forming a three-way alliance with Nippon Paper and Sumitomo Corporation under the restructuring pressure set off by Oji’s hostile bid for Hokuetsu; cross-shareholdings were a defence and a full merger was on the table. The 2008 crash pushed both companies back onto their own results, and in 2009 the alliance was dissolved. Rengo went alone.

Alone meant financing recovery from its own balance sheet. In 2010 the ¥2.9bn cost of winding up a subsidiary was offset by $74.1M (¥7bn) of gains on the closed Kawasaki plant site, leaving net profit at ¥7.8bn; in 2011 Rengo raised containerboard prices 10% into the recovery. Then the limit of that lever appeared: in June 2012 the Fair Trade Commission raided the company over price-fixing in board and containerboard, and the finding cost roughly $75.2M (¥6bn) in surcharges — an extraordinary loss of ¥5.9bn that took back what the price rise had won. In a commodity where nobody can differentiate, coordinated pricing is the natural growth lever and collides directly with antitrust law.

Geography did not work either. In July 2013 Rengo sold down its Chinese joint venture, beaten on its own integrated model by local players in a market growing far faster than Japan’s; a 2014 sale of the old Nagoya plant site — ¥9.6bn against a ¥0.2bn book value — again patched the balance sheet with land rather than boxes. So the company changed the product instead of the map. Heavy-duty packaging, entered in 2009 with Nihon Matai, became the export vehicle: in October 2016 Rengo paid $224.2M (¥24bn) for Hong Kong’s Tri-Wall, its largest acquisition ever, and roughly ¥32.3bn more for German heavy-packaging makers to build out Europe. At home it consolidated, ending containerboard production at Yodogawa in December 2017 — the site it had integrated in 1930.

The search for growth outside the box continues. In April 2024 Rengo combined its Sun-Tox subsidiary with Mitsui Chemicals Tohcello’s packaging-solutions business to form RM Tohcello, pulling functional-film forming inside the group. Roughly a 30% share of a mature domestic market still funds the company; what it buys with that cash is everything corrugated can no longer grow into.